Occupational Skills, Safety, and Environmental Protection
This domain tests everything around the pour rather than the concrete itself: trade math, drawing and specification reading, documentation, and the legal duties that govern a concrete crew's day.
Hazard controls you must know
- Wet concrete is caustic (pH roughly 12.5 to 13) and abrasive. Rubber boots, gauntlets, eye protection and long sleeves are baseline; wash skin immediately, because alkali burns can take hours to appear.
- Respirable crystalline silica comes from dry cutting, grinding, sweeping and blasting. Engineering controls come first: wet cutting, dust-extraction shrouds, HEPA vacuums. A fit-tested respirator is the last line, not the first.
- Confined spaces include pits, tanks and deep forms. Entry requires a permit, atmospheric testing, an attendant outside, and a rescue plan.
- Fall protection, scaffold inspection, lockout/tagout on mixers and saws, and WHMIS/GHS labels plus SDS for admixtures, release agents, curing compounds and epoxies.
Environmental control
- Wash water is high-pH and must never enter a storm drain, ditch or watercourse. Use a lined, bermed washout pit, let solids settle, then haul solids and water to an approved facility.
- Drip trays and spill kits for fuel and hydraulic oil; report releases as the regulations require.
- Segregate waste, recycle forms and rebar, and control dust and noise to local bylaws.
Worked example
A pump and two trucks will wash out on a residential lot. Identify the hazard (high-pH slurry), choose the control (a 3 m by 3 m pit lined with 10-mil poly, bermed, at least 3 m from any drain), and size it. Estimated wash water: two trucks at 150 L plus 250 L for the pump and hoses equals 550 L. The pit area is 9 m squared, so the water stands about 61 mm deep, well inside the 0.6 m depth. Settle, decant the clear water to a drum for disposal, and haul the solids.
Traps
Treating wash water as harmless and rinsing tools in the gutter. Choosing a paper dust mask for silica instead of proper controls. Relying on PPE where wet cutting would eliminate the dust. Entering a form or pit without testing the air.